Abstract: The invention relations to a hydroxylapatite gel obtained through a sol-gel process, in which an alkaline aqueous solution of a calcium salt is reacted with an alkaline aqueous solution of a phosphate salt in a calcium and phosphorous molar ratio in the range of 1.67 to obtain a sol. The sol is then transformed into a gel by hydrothermal treatment. The hydroxylapatite gel thus obtained exhibits excellent properties for use as a binding agent in moldable hydroxylapatite materials, comprising a granular filling material containing calcium in addition to the gel. The filling material is also preferably a hydroxylapatite material. Shaped bodies can be obtained from the hydroxylapatite material, which are most suitable for use in bone surgery as filtering materials. The invention further relates to a metal implant comprising a coating of the inventive hydroxylapatite material. The invention also concerns a method for producing the hydroxylapatite gel, the shaped bodies and the coated metal implant.